Band-wheel counterweight



July 24, 1928.

G. E. FENTRESS BAND WHEEL COUNTERWEIGHT Filed June 24, 1927 INVE/VTUP Patented July 24, 1928.

PATENT OFFICE.

GEORGE E. FEN TRESS, F LOS ANGELES, CALIFORNIA.

BAND-WHEEL. ooun'rnnwnrsn'r.

Application filed June 24,

My invention relates to rotating counterbalances and particularly to balancing the Weightof the pump rods and of a portion of the column of oil in pumping oil wells.

The object of my invention is to provide. a counterbalance which can be quickly put into and out'of service without lifting heavy weights and which, when not in use, hangs idle on a-rotating shaft. i A further object of my invention is to provide a counterbalance which does' not need to be bolted to the band-wheel and which is entirely self-contained.

In pumping oil wells the pump rods and plunger are suspended from one end of a walking-beam, tothe otherend of which is? attached an assembly consisting of 'a pit man or connecting rod, a crank, and a shaft revolvedby means of a band-wheel'driven by a suitable engine or motor.

The weight of the rods and of the'column of oil lifted by-the pump is a very heavy load on the up-stroke and it is customary to counterbalance a portion of this weight, thus to some extent-equalizing the load on the prime moverthrough the revolution of the crank.

This counterbalance is sometimes appliedas a dead weight on the crank end of the walking beam or an extension thereof, or" sometimesby bolting weights to' the side of the band-wheellying next the crank. It is advantageous to apply the counterweight to a rotating rather than to a reciprocating member, but application direct to the band wheel is undesirable inasmuch as neither this structure nor the keys by which it is retained on the shaft are of sufficient strength to withstand the high stresses set up by ,the change in direction' of .movement, of the weights. Again, the weights required are very heavy and moving and. bolting them into place is a laborious job which must be performed each time the well is taken off the pump, as for pulling rods or tubing.

To overcome these disadvantages while retaining the desirable'features of a rotating counterweight I suspend the weight from the shaft in such manner that it may hang free and motionless on the rotating shaft while pulling the well and may be locked so as to revolve with the shaft while pumping,- with the expenditure of a minimum of time and labor. v

A preferred embodiment of my invention 1927. Serial No. 201,153.

is illustrated in the attached drawings, in I counterweight approximately on the line 22 of Fig. 1.

Fig. 3 is a plan view of one of theadjusting weights 25 indicated in Fig. 2.

Referring to Figs 1 and 2-1 is the band wheel shaft with the band-wheel 2 mounted thereon. jack-post bearing-box 3 to wheel ,clutchsprocket, not shown, to be secured on the broken projection .4. Intermediate the band-wheel and the bearing-box 3 is a cylindrical collar-5, bored to a press fit on the shaft, and secured thereon by a plurality of heavy keys as at 6. As indicated in the drawing, this collar should be of materially greater diameter than the shaft, to-

enable the collar to be firmly keyed to the shaft and to give clearance over the shaft for the removal of taper pins 9.

Surrounding this collar is a bearing-box split into the halves 7 and 8, bored to a running fit on the collar which is thus permitted to rotate within the bearing-box while pulling rods or tubing. collar is prevented from rotating inside bearing 7 8 by inserting the taper pins 9 into corresponding bores formed partly in the collar and partly in the bearing, and draw ing them tight with the nuts 10. These'pins act as keys, causing the bearing and the weight which is attached to it to rotate with and'iaroundthe shaft.

' The operation of putting the counterweight .out of commission thus resolves itself to dropping the weight to its lowest position, to relieve the strain on the pins, backing off the nuts and driving out the pins.

The weight then hangs suspended on the collar 5 which revolves freely within the bearing 7-8. The weight is put into use by revolving the shaft until the halves of the pinholes register, inserting the keys and drawing them up with the nuts. Either operation may be performed by one man in a few 'minutes without any other tool than aspanner and a hammer.

The ends of the bearing halves 7 and 8 are extended to form the lugs 11 and 12, which The shaft extends through the Y permit the calf- When pumping, the

j are faced to a close fit at 13 when the halves are adjusted to running fit on the collar 5.

The tapered holes 33 are bored through the assembled bearing. The rods 14 have square heads as at 21, a taper at the. opposite end to fit the holes 33, and a threaded projection fitting the nuts 17, and for substantially the remainder of their length are threaded to fit the nuts 24:. These rods fit snugly in the round holes 20 through the main weight 19, the square heads being let into square cored holes in this weight. These rods are preferably provided with the square" shoulder 18 against which lugs 11 and 12 may be tightly drawn by the nuts 17. The rods 14: should be large and stifi, in proportion to the weight to be carried.

The adjusting Weights 25 shown in Figs. 2 and 3 may be of any desired thickness, and are preferably of the same plan shape as the inner plane surface of the weight 19. They are formed with a lug 28 which is one-half the thickness of the body of the weight, this lug being drilled through at 29 to fit loosely over the stud 26 which is threaded into the weight 19 at the central point on its inner face. These lugs may have the rounded end indicated at 28, and a slot as at 31, this slot being of a width to slip readily over rod 14. The center spacing of slot 31 from hole 29 is the same as from rod 14 to stud 26.

These adjusting weights may be added as requiredto the main weight 19 by removing nut 27 and backing up nuts 24, slipping one or more'pairs of weights, with lugs overlapped; over the stud 26, swinging the Weights until the slots surround the rods 14, and tightening nuts 27 and 24:.

The flange 32 formed on the upper half 7 of the bearing box 78 is to retain this box revaaee against end movement on the collar 5 when the pins 9 are removed.

While I have described a complete embodiment of my invention 1 do not wish to be limited to the particular construction shown, my invention being in fact limited solely by the attached claims.

I claim as my invention:

1. A counterweight for use on a rotatable shaft, comprising: a journal surrounding said shaft and firmly keyed thereto; a split bearing box fitted to revolve on said journal; lugs projecting from each half of said box and rods depending therefrom, the upper end of each said rod being shouldered, ta-

pered and threaded to pass through one of said lugs; threaded nuts on said upper ends to hold said box in rotatable contact with said shaft when said nuts are drawn tight,

a weight rigidly, attached to the lower ends of said rods, and a plurality of readily removable taper pins fitted transversely'between said box and said journal and adapted to preventrotation of said journal within said box. i

2. A counterweight for use on a rotatable shaft, comprising: a journal of diameter materially greater than that of the shaft, firmly rounding said journal and freely rotatable thereon; readily removable taper pins fitted have hereunto subscribed my name this 15th day of June,

' .enonenn. FENrREss'.

aflixedto said shaft; a bearing box sur- 

